DNA detection based on capacitive AL/sub 2/O/sub 3//AL microelectrodes

The electrical detection of DNA hybridization still faces the challenge of detecting very low concentrations. In this work we present the possibility of detecting DNA probes by measuring a capacitance change between interdigitated aluminum micro-fingers coated with a thin alumina layer and constructed over an oxidized silicon wafer. DNA Labeling was performed by biotinylated nucleotides and reaction with anti-biotin/gold nanoparticles, increased in size by silver crystal precipitation. The capacitance change ratio observed was at least of two, using 0.2 nM DNA solutions. This detection method appears compatible with microarray technology and paves the way for further use in biological applications.